Question

Why we get errors while performing an experiment?

Answer 1

What is an Error ?

Error is the discrepancy between your results and what would be predicted or theoretically possible. Depending on the experiment, different levels of error are permissible, but generally 10% is seen as acceptable.

No matter how well you conduct an experiment, there will always be some degree of uncertainty or inaccuracy. You are measuring against a standard using an equipment that will never be able to replicate the standard completely, and because you are human, your technique may introduce inaccuracies.

Systematic errors, random errors, and personal errors are the three basic types of errors.

1. SYSTEMATIC ERRORS :

All of the measurements you make are subject to systematic error. These errors will all be in the same direction, and there is no way to account for them by gathering more information.

Incorrectly calibrated or improperly used measuring equipment is typically the root cause of systematic mistakes. However, they can enter your experiment through a variety of places, such as a damaged instrument. For instance, a plastic tape measure gradually stretches over time, producing measurements that are just a little bit too high. A scale that does not read zero when nothing is on it is an example of an instrument that has been improperly calibrated or tared. A person consistently measures incorrectly. For instance, they might believe that the 3/4" and 2/3" marks on a ruler are the same.

2. RANDOM ERRORS :

Variations in the experimental or measuring settings are the cause of random mistakes. These faults are typically minor. More data is typically collected to lessen the impact of random errors.

It may take a while to identify the sources of random errors because they are sometimes not immediately apparent. The measurement device and how it is affected by changes in the environment might also lead to a random error. For instance, a spring balance may exhibit some measurement variation as a result of temperature variations, loading and unloading conditions, etc. A measuring device with more precision will have less volatility in its readings.

3. PERSONAL ERRORS :

You should not use "human error" as a source of error in a lab report. Instead, you should make an effort to pinpoint a specific error or issue. Going into an experiment with preconceived notions about whether a hypothesis will be accepted or rejected is a typical personal mistake. Lack of expertise using a piece of equipment is another common personal error; if you have some experience, your measurements will likely be more precise and trustworthy. Simple mistakes, such as using the wrong amount of a chemical, timing an experiment incorrectly, or skipping a protocol step, are another sort of human error.